Manufacture of vat dyestuffs



Fatented June 28, 1927.

STATES PATENT OFFICE PAUL NAWIASKY, 0F LUDWIGSHAFEN-ON-THE-RHINE, KARL ZAHN, 6F EOCHST-ON- THE-MAIN, AND KARL SA'URWEIN, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNORS TO I. Gr. FARBENINDUSTRIE AKTIENGESELLSCHAFT, 0F FRANKFORT= ON-THEMAIN, GERMANY, A CORPQRATION OE GERMANY. 1

MANUFACTURE OF VAT DYESTUFFS.

No Drawing. Application filed November 23, 1925, Serial No. 71,020, and in Germany December 13, 19%.

We have found that new valuable vat the formula (to which, however, we do not dyestuffs can be obtained by treating ethers wish to bind ourselves) of hydroxy-benzanthrones substituted by halogen in,the Bz-l-position but with a free 2-position, with alkaline condensing agents. The new dyestuffs which are believed to be members of the isodibenzanthrone series, are distinguished by their very beautiful tints and by their good tastness.

The following example will serve to illustrate further how the invention may be carried out in practice, but the invention is not limited to this example.

The parts are by weight.

t I Example.

7 parts of 'Bz-1-chlor-Bz-2-methoxy-benzanthrone corresponding to the formula (obtained for example by treating Bz-2- methoxy-benzanthrone with sult'uryl chlorid in nitrobenzene solution or by methylating BZ-Tl-chlor-Bz-2-hydroxy benzanthrone obtainable by chlorinating Bz-Q-hydroxy-ben- 'zanthrone) are introduced into a melt prepared from 28 parts of caustic potash and 28 parts of alcohol, at 135- degrees to 14:0

degrees oenti'grade. The mixture is stirred for about an hour at 145 degrees to 150 degrees 'centigrade, thereupon diluted with water and boiled; The dyestuii' is then precipitated by aerating, filtered ofi, washed until neutraland made into a paste.

The new dyestufi to which we attribute gives a pure blue vat from which, cotton is dyed the same color. By the oxidizing action of the air, the color is changed to a bright greenish blue. The d estufi' dissolves in concentrated sulfuric aci claret red. It can be purified by boiling with indifierent solvents for example dichlor-benzene, or by fractionally precipitating from sulfuric acid From other ethers of hydroxy-benzanthrones halogenated in the Bz-l-position and with, a free 2-oosition, .dyest-ufls can be obtained in a similar manner.

We claim: l v 1. The process of manufacturing new vat dyestuffs which consists in acting on ethers of hydroxy-benzanthrones halogenated in the Bz-l-position and having a free 2-position with an alkaline condensing agent.

vat dyestufl which consists in acting on Bz- 2. The process of manufacturing a new -a claret red coloration and dyes cotton from 10 a blue vat blue shades which by oxidation 1-chlor-Bz-2smethoxy-benzanthrone with an turn to a bright greenish blu-e. alkaline condensing agent. In testimony whereof we have hereunto 3. As .a new article of manufacture a Vat set our hands. dyestufi which can be obtained by acting on Bz-1-chlor-Bz-2-meth0xy-benzanthrone PAUL NAWIASKY. with an alkaline condensing agent and which KARL "ZAHN. dissolves in concentrated sulfuric acid with KARL SAURWEIN. 

